Rewind Starter Spring won't stay secure. Wheeled Weed Trimmer 917.773704?

I have replaced the starter rope and spring appears set on Housing spindle center and assembly pulley outside. prior to reassembling the B&S engine housing the starter rope retracts. Upon reassembly the first time I pull to start engine. The spring comes free on the Housing Spindle. I am obviously missing a trick to securring the spring in the Center.